Mr. Pilati, who next year will celebrate his 10th anniversary of designing Yves St. Laurent, created skirts for this fall with slits all the way up to here.

The slits of some skirts were incorporated into pleats, giving a surprise glimpse of thigh as the models strutted.

Designers do those things because it’s eye-catching on the runway, and it’s invigorating to fashion editors who have seen nearly everything already. It’s more likely to get their collections chosen for editorials, and to generate the all-important buzz in the fashion community.

But few women will be buying skirts with slits nearly to their hips, so retailers will mostly buy something else, or YSL will produce them without the slits.

That’s an everyday solution in fashion, and it’s why runway looks are so rarely seen on the streets.

I don’t think it was Mr. Pilati’s most exciting collection. But other parts struck a more graceful balance between art and wearability.

Several voluminous jackets – one in particular that mixed the gray plaid with black knit – were two-thumbs-up.

And a purple plaid skirt that morphed to strands of feathers floating at the hem was lovely.